Validity of Self-reported Endometriosis

A Comparison Across Four Cohorts

A.L. Shafrir; L.A. Wise; J.R. Palmer; Z.O. Shuaib; L.M. Katuska; P. Vinayak; M. Kvaskoff; K.L. Terry; S.A. Missmer


Hum Reprod. 2021;36(5):1268-1278. 

In This Article


The proportion of cohort participants who did not respond to mailings or had an undeliverable address ranged from 8% for NHSII first wave to 70% for BWHS (Table II). Among those contacted, 12.5% (BWHS), 16.8% (GUTS), 1.5% (NHSII first wave), and 10.8% (NHSII second wave) denied their original report of an endometriosis diagnosis. These data were not available for the E3N cohort. Of those who were contacted and did not deny their original report of an endometriosis diagnosis, 19.7% (BWHS), 91.5% (E3N), 36.7% (GUTS), 75.6% (NHSII first wave), and 56.8% (NHSII 2 wave) provided permission to obtain their medical records for review.

Among those who confirmed their diagnosis and consented to records procurement, relevant medical records were obtained and reviewed for 827 women: n =225 (BWHS), 168 (E3N), 85 (GUTS), 132 (NHSII first wave), and 217 (NHSII second wave) (Table II). We excluded 30 participants for having irrelevant medical records, as the only documents we received were unrelated to either primary care physician, surgical, or gynecologic visits. In the NHSII second wave, 211 participants had information to inform their surgical confirmation; for six individuals a pathology report but no surgical report could be procured. We noted that all six of these participants had documentation in their pathology reports of histologically confirmed endometriosis.

Among those for whom relevant medical records were reviewed, the overall confirmation proportion of self-reported endometriosis diagnosis was 84.4% (698/827), ranging from 72% for BWHS to 95% for GUTS (Table II). A pathology report was available for only 42% of surgeries (Figure 1). Among participants with surgically confirmed endometriosis, the overall histologic confirmation proportion was 92% (133/145) and ranged from 76% for GUTS to 100% for NHSII first wave (data not shown). When validation was restricted to those who self-reported a laparoscopic confirmation of their diagnosis, the overall confirmation proportion rose to 97% (367/379), ranging from 95% for NHSII second wave to 100% for NHSII first wave (Table III). Among participants for whom endometriosis was suspected prior to surgery but not visualized at surgery (surgically disconfirmed endometriosis), there was often documentation of other conditions, such as uterine fibroids or endometrial polyps, that are associated with symptoms common among women with endometriosis (e.g. chronic pelvic pain), as opposed to having no evidence of pathologic disorders (data not shown).

Figure 1.

Availability of histologic, AFS/rASRM stage, and endometriosis phenotypic characteristics from medical records. Percentage of Nurses' Health Study II 1st and second wave (NHSII W1 and NHSII W2) and Growing Up Today Study (GUTS) participants with surgically confirmed endometriosis who had a pathology report or information within the surgical record noting: American Fertility Society (AFS) or revised American Society for Reproductive Medicine (rASRM) stage; presence or absence of deep endometriosis; or presence or absence of endometrioma.

In secondary analyses, among participants who did not self-report a laparoscopic confirmation in the NHSII and GUTS, the overall confirmation proportion varied substantially among cohorts—ranging from 56% in NHSII first wave to 100% in NHSII second wave—although these estimates were based on small sample sizes (Table III). Among the women who did not self-report a laparoscopic confirmation but were found to have a report of surgically visualized endometriosis within their medical records, six had a hysterectomy (NHSII) and the remaining four (GUTS) received a clinical diagnosis before their laparoscopic surgery. In the BWHS, confirmation proportions were somewhat higher among women who had reported laparoscopic confirmation on their questionnaire—74.8% (134 of 179)––as compared with those who had not reported laparoscopic confirmation—61.8% (28 of 46) (data not shown). However, the first two (1995 and 1997) BWHS questionnaires did not ask about laparoscopic confirmation of endometriosis; therefore, some of those in the group who had not reported laparoscopic confirmation would probably have reported laparoscopic confirmation if asked, thereby raising the first proportion and lowering the second. The overall confirmation proportion did not vary between NHSII second wave participants who were never infertile (94.9%) compared with those who concurrently reported infertility and an endometriosis diagnosis (95.2%; Supplementary Table SI). However, the surgical confirmation proportion was higher in the concurrent infertile group (98%) compared with the never infertile group (89%).

For GUTS and NHSII 1st and second waves, attempts for abstraction of details on stage (AFS or rASRM when available), histologic findings, and visualized endometriosis macro-phenotypic presentation (endometrioma(s) and deep endometriosis) from the medical records showed that this information was most often absent (Figure 1). The proportion of medical records among participants with surgically confirmed endometriosis and any stage information varied from 13% in NHSII second wave to 44% in NHSII first wave. Only 3% of NHSII second wave and 6% of GUTS records mentioned the presence or absence of deep endometriosis among participants with surgically confirmed endometriosis.